While popularization of third generation communication systems was slow due to imbalanced development of mobile communication and mobile computing, fourth generation communication has been rapidly developed since computing environment rapidly changes from a personal computer such as desktop computer, notebook computer, etc. to personal information devices such as a smartphone, tablet, etc. Particularly, recently developed cloud computing environment requires organic combination of communication and computing of a high level, accelerating development of fourth generation communication. As LTE-Advanced and WiMAX-Advanced have been approved as fourth generation IMT-Advanced standards by ITU, discussion of fifth generation mobile communication system has begun. ITU-R WP5D in charge of IMT performed various activities for attracting interest in fifth generation communication, such as holding local workshops in the name of “IMT for the Next Decade” in 2011. In addition, WWRF conducted research on NG-Wireless system requirements and vision and published the first report. As communication service environments have remarkably changed over the past 10 years, it is very difficult to predict changes over the next 10 years. Communication standardization organizations such as ITU-R, WWRF, etc. consider the following factors of changes for 5G communication environment for 2020.                Development of multimedia services focusing on high definition video service        Provision of differentiated UX (user experience) through personalization service: provision of services suitable for preference, situation, equipment, etc. of a person.        Communication environment change from device to user: provision of user centric services is required as a user owns a plurality of communication devices. Content sharing, provision of seamless mobility between different devices, provision of security services.        Extension of M2M service: traffic increase through extension of M2M devices and provision of new M2M based services are needed.        Extension of mobile cloud computing environment: all computing environments are combined with networks to provide mobile cloud computing through provision of communication environments having low latency and high performance.        
According to the above-described service environment variations, the following is under discussion for essential requirements of the 5G communication system.
Bandwidth/Throughput Improvement
According to various analysis reports, it is expected that the number of mobile devices and traffic increase on a large scale over the next 10 years. In case of mobile device, it is expected that low-end terminals will be replaced by Internet terminals such as smartphones, tablets, etc. and the number of connected terminals such as M2M devices remarkably increases although increase in the number of mobile device users is slow. According to Cisco's report, mobile traffic increased six-fold from 2008 to 2010 and is expected to increase 26-fold until 2015 to reach monthly 6.3 EB (Exabyte, 1018=260 bytes). UMTS Forum anticipates 3.8 EB in 2010 and 127 EB in 2020, which is 13 times the mobile traffic in 2010, with reference to data of IDATE. During this period, the number of mobile terminals is expected to increase from five billion to ten billion. According to this trend, it can be seen that the first goal of a fifth generation mobile communication system should be increased throughput. While there are various methods for increasing throughput, a first available method is to discover and use unused additional bandwidths. While current mobile communication systems use bandwidths of lower than 3 GHz, research on higher bandwidths is performed due to limited bandwidth. Particularly, ensuring system performance according to changed frequency characteristics in a high frequency band of 2 to 6 GHz is under study.
Provision of Uniform Service Quality
While 4G communication systems have been improved to realize 1 Gbps in terms of data throughput, service quality non-uniformity is serious such that there is a more than 30-fold difference between average spectrum efficiencies of cells and cell edges. It is very important to improve this non-uniform service quality due to the motto “provision of desired services any time anywhere” that is required for 5G communication.
Accordingly, research on performance improvement in cell edge areas is performed through technology such as WiFi offloading, addition of subsidiary cells such as Femto BS, eICIC (Enhanced Inter-cell Interference Coordination), COMP (Coordinated Multi-Point), etc. in 4G communication systems. However, it is necessary to provide uniform services of a higher level.
User Centric Organic Interoperation
While interoperation of devices is achieved on the basis of user manipulation or determined policy in the 4G system, next generation communication systems require techniques for providing services of the same level in various communication environments including organic interoperation of devices with diversification of user device. That is, it is necessary to provide techniques for achieving organic interoperation of technologies such as cellular and wireless LAN without a complicated process and providing optimized services in an optimized environment while minimizing user intervention through seamless provision of all services.
To meet the aforementioned requirements, much research is underway and, particularly, research on communication networks is carried out. However, a method for efficiently updating a tracking area by a UE in a C-RAN system has not been researched.